A heat exchanger costs ₱36,000, but it will save ₱5000 per year in energy costs. If the interest rate is 10% compounded semi-annually, how many years does it take to recover the capital cost?...

A heat exchanger costs ₱36,000, but it will save ₱5000 per year in energy costs. If the interest rate is 10% compounded semi-annually, how many years does it take to recover the capital cost?

Solutions manual only with formula, without using Microsoft Excel.